Our transcription: The rapid current of a sediment-laden river can also generate a sandblasting effect, which can scour its way down through sediment or even solid rock.In this process called "abrasion" the energy of the moving water is converted into collisions between sedimentary grains and the bedrock at the channel bottom.Abrasion not only smoothes river cobbles into rounded shapes, it can also wear away the bedrock many times faster than hydraulic action alone.